In copper plating, a current of 0.5A is allowed for a cathode area of 100cm2. If this current is maintained constant for 100mins, calc. the thickness of the copper deposited. [electrochemical equivalent of copper=0.00033gC-1, density of copper=10000gcm-3]
To calculate the thickness of the copper deposited during copper plating, we can use Faraday's law of electrolysis.
Faraday's law states that the amount of substance deposited or liberated at an electrode is directly proportional to the quantity of electricity (charge) passed through the electrolyte.
In this case, we have the following information:
Current (I) = 0.5A
Time (t) = 100 mins = 100 x 60 = 6000 seconds
Cathode area (A) = 100cm^2 = 100 x 10^-4 m^2
Electrochemical equivalent of copper (Z) = 0.00033 gC^-1
First, we need to calculate the total charge passed through the electrolyte using the formula:
Total charge (Q) = Current (I) x Time (t)
Q = 0.5A x 6000s
Q = 3000 Coulombs
Next, we can calculate the mass of copper deposited using the relation between charge, electrochemical equivalent, and atomic mass:
Mass (m) = (Q / Z) x atomic mass
The atomic mass of copper is 63.55 g/mol.
m = (Q / Z) x 63.55 g/mol
Finally, we can calculate the volume of the copper deposited using the formula:
Volume (V) = Mass (m) / Density of copper
The density of copper is 10000 g/cm^3.
V = m / 10000 cm^3
By rearranging this equation, we can find the thickness (d) of the copper deposited:
d = V / A
Let's calculate the thickness using these formulas:
Step 1: Calculate the total charge passed (Q):
Q = 0.5A x 6000s
Q = 3000 Coulombs
Step 2: Calculate the mass of copper deposited (m):
m = (Q / Z) x 63.55 g/mol
First, we need to convert Coulombs to moles by dividing by the Faraday constant (F) which is 96500 C/mol:
m = (3000 C / 96500 C/mol) x 63.55 g/mol
Step 3: Calculate the volume of the copper deposited (V):
V = m / 10000 cm^3
Step 4: Calculate the thickness of the copper deposited (d):
d = V / A
Now, let's substitute the values and calculate the thickness of the copper deposited.
coulombs = current x seconds
C = 0.5A x 100 min x (60 sec/min) = 3,000 C
0.00033 g/Coulomb x 3,000 coulombs = 0.99 g Cu deposited.
Now a problem. There is no way the density of Cu is 10,000 g/cc. The density of Cu is 8.96 g/cc so I will round that off as 9 g/cc. You may have meant to round it to 10.000 g/cc.
mass Cu = volume x density
0.99 = volume x 9 g/cc
v = 0.99/9 = 0.11 cc
The area plated is 100 cm^2 or let's say 10 cm x 10 cm.
volume = length x width x thickness
0.11 = 10 x 10 x thickness. Solve for thickness. After you have corrected the problem for the density you can follow this procedure to determine the thickness. Post your work if you get stuck.